Driven pressure bar eor veneer machines



Patented Sept. 6, 1927.

PATENT OFFICE.

GEORGE H. OSGOOD, 0F TACOMA, WASHINGTON.

DRIVEN" PRESSURE BAR FOR VENEER MAEINES.`

Application filed August 11, 1926. Serial No` 128,628.

This invention relates to machines for cutting a sheet of veneer from a block of wood, or a log, and has special reference to the pressure bear thereof, whichv` engages the wood at a point adjacent to but spaced from the cutting edge of the knife to prevent the splitting or breaking of the wood. The object of my invention is to improve the action of the pressure bar on the Wood by causing the contact member of the bar to rotate therein, while being pressed on the block as it Vpasses the bar, at au speed greater than a certain predetermined speed, thereby reducing the breaking of the wood fibers by the pressure bar and eliminating the delays and losses due to the accumulation ofslivers and soft wood which become wedged in the space between the .log and the pressure bar when a punky, soft, or rotten spot in the log is cut, and which preventthe free rotation of the said rotary contact member, unless such member is independently rotated to pass the said accumulated material away. A further object is to permit the veneer tobe cut from a cold dry log, thereby preventing the spreading of the heart checks of the log to the circumference thereof and therefore producing a greater Varea of acceptable veneer per log-foot than can be done when the log must be steamed, the saving in this respect alone amounting in practice to a considerable amount as hereinafter shown. A further object is to provide a plurality of sets of bearing blocks which together hold the rotary contact member from falling out between them and which firmly hold it in the pressure bar and apply its pressure thereto uniformly from end to end of the log, independentof the wear of the contact member or of the said bearing blocks.

I attain these and other objects by the devices, mechanisms, and arrangements illustrated in the accompanying drawings, in which-- Fig. 1 is a cross section of my improved pressure bar mounted in a veneer lathe and showing `the cooperating parts whereby the veneer is cut from the log; Fig. 2 is an elevation of the end of the rotary Contact member and its auxiliary driving mechanism, showing a part broken away to reveal the construction thereof; Fig. 3 is a crosssection thereof; and Fig. 4 is a plan view of a portion of the series of bearing blocks.

Similar numerals of reference refer tol similar parte throughout the several viewsV Referring to the drawings, it isunder'- stood that'the log 1 is rotated by suitable means and that the knife 2, mounted on a suitable carrier 3, engages the said log and is fed inwards towards the center of rotation of the log 1 by suit-able mechanism in constant relation to the rotation of the log in the lathe, thereby turning a sheet of veneer l from the log; also, that the pressure bary 5, and all is apparatus, is also fed inward at the same rate and in constant relation to the said knife 2 and carrier 3 by suitable mechanism. The rotating and feeding means beingicommon in the art are not illustrated herein..

` One of the important ,characteristics `of a veneerllathe to be remembered in the consideration of this invention is that the feed lof the knife 2 and pressure kbar 5 must be radial from the center of rotation of the log l, and that the cutting edge of the knife 2 must lie substantially on the same radial Vline,`else the angle that thecircumference of the log makes with the knife would change with the change in the diameter `of the log as it was reduced by the action of the lathe; and also it is necessary that the surface with which the pressure bar bears on the wood shall lie substantially on the same radial line and be vin close and fixed relation to the cutting edge of the knife.

The pressure bar comprises a very heavy and stiff carrier 5, of general triangular shape, having one of its angles adjacent the log 1, and withtwo enlargements 6, one on each side of said angle, to form its nose. A cavity 7 is formed in the nose of the pressure bar `and extends from end to end thereof and is adapted to receive the hereinafter described roller or contact member, which does not however touch its walls. A plurality of wide channels 8 and y9 are cut inward from the outer' edge of the nose of the pressure bar 5 and extend from end to end thereof, each channel having parallel sides. lVhen two such channels are used, as shown in the drawings, their inner or adjacent sides are made radial from the center of the rotating contact member and are substantially parallel with the correponding "sides of the triangular pressure ar 5. i

A plurality of bearing blocks 10 are- Y sait boating lolotlos. ,lll .alle 1l ft Steely ln .their respective elfiannele and are pressed loutward therein by means of lthe adjusting screws 12,

passing through the said enlargements '6' and entering the said channels"8 and 9.

` The upper corner of the'fro'nt or outer end lower corner of thev 'front or outer end ofk eachy of the bearing blocks 11 is'lcut away to'form a surface substantially parallel with the lowei"fro1it surfacerof lthe lower einv largement 6 While Ktheupper corner thereof loffeifloovesl to fit tho .Sulfato ol tho Cylintliloal 'tolling oontaot tioiiibor. hold .thoroby.- {Tllo' twosalfl blooks l0 tool ll' envelop a' large portion` of the circumference of the rolling contact member, their outer edges being .tonal-'ated ttt-oat .ont rleht-tloelolaport intl their lll-nor ttleos.. .tolte about forty-.five degee's apart. Thus it will be seen that the the. 'Spaoe'botiioorl the outer otleoo. of the re- .Sptotlio bootleg lolooke when ollooneegool., troni the legend .that Ithe pressure derived from ,tlio ofllro'r .5 bym-oats' ofthe adjust* lne Soltero.-v 12 lo tltlllomlttool tlll'olleli the4 sleyer'al` bloeks 1.0i. andV 1l to the rolling conedge of the knife 2 'is positioned', lrelativevely Y toflfllo, oolltol ifl'ycrcumferenco .Q the bali 1.3, Stoll that tllo. roer .Surfaoo .of tlle. Cutting otlee .is slibotantitlly tanoontlol to tho di'a'l'line theretoy ihrem the center of the said roller 1.3, and thereforsince the llalnetor'of the rollollltl Smell, the sheet off vente? l., Whiehis beingntolocl .off tlioA l Flog l', .is permitted to leave. the back .Surface ot'tlfo limito! 2 Vlttlifrlostal ono@ ,ldyot p'olf mieii1^leii knit-12. io b@ Oi subsane flakes. 'The 'smeltwater afin@ alle be? 1,5. is Very importent'. in y.the pmotoal Wolf-tine out fof soot?? ioohlio. at 'lt foto@ that@ the diameter is increased but slightlyV either the lnife" must be made too thin ardor to biting its olittleg ode@ le llaa l@with ftlio'ertsatood lts rear Sulfato 'teaeeltlal to thefollorlo'r, thotoller must be 'mor-od contact member cannot fall out throughaway from the cutting edge of the knife to Pfrollioo Sttisfaotiory vorieer. Als'o'silloo the rollerbalr 13 is of small diameter` and the pressure comes inv proper relation to the Y.

knife, the Wood is notoverstrained by the cuttin action and it is thus possible to cut cold logs therewith; This fact vresults in,y a large saying in that is eliminates the necessity of steaming oifboiling the' logs for Y many hours, thus saying the time indexii-lolio-o .illololollt thereto and. lmpfovmg .tto foolidltlolls ol greater produetion of satisfactory VVeneer bootet@ tllo hoort Check, .usually eroont ln 'the .Core of the loe, .Spoatlo to the .clncuin-y llollto of tho' oe @der tho aotlon of. tllo steen; .or Vllot water; .and this roiilts in a .ooliffltlerable loss. in trimming tho ledges of the checked Veneer, in( fact'yvhere Was rosslblo to. produc@ lo? Square feet of throof ily Ptlliolllle'nor"logffoot from 'a Stoalloflloa it'l'ilow pojoolt o to. prodigo@ 2:95 Sauafoot from ool log, an inoltase .of .output of abo t crease in expense o f production.

Tlloftollttliai 13 1S rotatd'byimoano'ol tto otloll lottato-l1 it and thosu'faoo of the', lol; gelost 'Wl'lloll it ls. proseefl and .tllorof loro otzitte With-'a oulotttlltally equal lof. il ,llolffil Speed to that ol' .tho .loef llowovtl as. alloro ldotorlliodl it lo loaokotl by milano? .of boating blools lOI end, ll., Wllloll oXtoll-.tl filete' its" ,ootllzo length, and tlipo friction tliolepf toads to totard the .tomtlonfoif tho Seid tar Unolol ordinary Conditie-.fle that. lSto allot tllo portion o'tllo loe beleg' .out elootl. tho .driving friction lo. frotter than. 'the itc-.outline flfloltiofl, oSPolofil-ly it.' Sal'olloloolto alo alittle of o lrlotttlf whoto ooi-Y ollololit offrir/tion Wltll tho i'ollor bei' lo. loin @ed tlio bi1* 13, lo tlioiotoro loreto/tl; Bilt 11.11-, itoi'tunately ideal conditions are not found in. .ovoly loe and? il 'o Portlet of tllo loe oon? tainssoftfpunly, or rotten spots",l rthen the driving friction the/reef is 'greatly redncel and. blotoililoi loos than, the l'ttllttliole tritt-loll of the bearing blocks1 with lthe result-that tho but: l .no loHeaf`rotatoff--. This @alles some or' the said soft wood to pile up and hoo-omo iio'tle'tt' totwollli' the loe' and 'tho bloot. .l0 or tho. .olllaleomeut 6 .ol tho Pfos- Slllo hol' itself and tl'lS '1.11 turn Hooosstatet.

a stoppage of the vlathe and the` clearing ille' woont lottllel oaldrollr loot 'l-Where by; when Conditions" et@ termal .Stile @exil-l.

opted. ol lotat'oaolf tho'tefflf "dto .to thlo @efr-lotions falls lotloiv a oertfttprodott- @nel imottltithoo. the. Said ettolitri." ap:

35% with' a flo-L- Ylary drive' is inefeetive butfasl. spoil as the.

paratus drives the roller bar at such minimum speed and thus forces all the slivers and other accumulated matter to pass the roller. This action therefore largely reducesl the number of times that the lathe must be stopped for clearing the. wood from the pressure bar and greatly increases the efficiency of the plant as it permits a more nearly continuous operation ofthe lathe than could formerly be attained. This apparatus comprises a suitable driving means, which may be the lathe itself or, as illustrated, an additional motor 14 mounted on the end of the pressure bar 5 and actuating a suitable gear 15, over which a chain or belt 16 passes, said chain 16 driving a similar gear 17 loosely mounted on the said roller bar 13. A ratchet mechanism is interposed (Figs. 2 and 3) either between the roller bar 13 and the gear 17, as shown, or between the motor 14 and the gear 15, in which latter case the gear 17 would be fixedly mounted on the roller bar 13. This ratchet mechanism, as illustrated, comprises a series of ratchet teeth 18 cut in the bar 13 and a ratchet dog 19 mounted in the loose driven gea-r 17 and thrown into contact with the teeth 18 by the spring 20. It is evident that if the roller bar 13 is rotated by the friction of the logl faster than the gear 17 rotates the ratchet dog 19 simply slides relatively backward over the teeth 18, but as soon as the gear 17 turns faster than the roller bar 13, then the dog 19 engages one of the teeth 18 and turns the said roller bar 13 at the same rate. Thus this mechanism therefore prevents stoppage of the roller bar 13 so long as the driving means is operated, and prevents the formation of a wedge of wood between the log and the pressure bar. If the speed of the gear 17 is adjusted to be about equal to that of the roller bar 13 when the diameter of t-he log is reduced to j the limit at which the lathe can cut, then the speed of the roller bar 13 will normally be greater than that of the gear 17 for all diameters of the log greater than such minimum diameter, and such auxiliary driving mechanism will be ineffective except when bad spots are reached in the log as above outlined.

Having, therefore, described my invention, what I claim is 1. A veneer lathe pressure bar comprising a strain-carrying member fed in xed relai tion to the surface of the log in the lathe; a cylindrical roller bar mounted in said straincarrying member and adapted to apply pressure on the log at a point adjacent the cutting edge of the lathe knife, said roller bar beingadapted to turn freely on its axis under the action of the friction between it and the log; and means adapted to rotate said roller bar when its speed of rotation falls below a predetermined rate.

2. A veneer lathe pressure bar comprising a strain-carrying member fed in fixed relation to the surface of the log in the lathe; bearing blocks mounted .in said strain-carrying member and each having a cylindrically concave 'groove at its outer end; a cylindrical roller bar mounted between said bearing blocks and held thereby in said grooves and adapted to apply pressure on the log at a point adjacentthe cutting edge of the lathe knife, said roller bar being adapted to turn freely on its axis in said bearing blocks under the action of the friction between it and the log; and means adapted to rotate said roller bar when its speed of rotation falls below a predetermined rate.

3. A veneer lathe pressure bar as set forth in claim 2, wherein said bearing blocks are movable in said strain-carrying member, to-

gether with adjustable means interposed between each of said bearing blocks and said strain-carrying member whereby the position of each said block may be adjusted.

4. A veneer lathe pressure bar as set forth.

in claim 2, wherein each said bearing block di subtends an arc of less than two right-angles of said roller bar, and wherein the outer edges of said bearing blocks are separated by less than two right-angles whereby the said roller bar is held in the blocks when disengaged .from the log.

5. A veneer lathe pressure bar as set forth in claim 2, wherein said roller bar rotating means comprises a wheel driven at a predetermined minimum rate of rotation, together with ratchet means interposed between said wheel and said roller bar whereby, when the roller bar turns faster than said wheel, said rotating means is ineffective, and whereby, when said roller bar tends to turn at a slower rate than said wheel, said ratchet means becomes engaged and turns the. roller bar at the same rate as said wheel.

GEORGE H. OSGOOD. 

